Indie actor Mark Ruffalo says he found himself on the Pennsylvania Homeland Security office's terror watch list for organizing screening of an oil-drilling documentary.

According to the World Entertainment News Network, Ruffalo -- who has starred in such films as The Kids Are All Right, Eternal Sunshine of the Spotless Mind and Zodiac -- told GQ magazine he found it "pretty f--cking funny" that he would be suspected of terrorism for raising the alarm about what many say is an environmentally harmful way of drilling for oil and gas.

Ruffalo has been promoting GasLand, a documentary that focuses on hydraulic fracturing, or "fracking." It's a process of drilling for oil and gas that involves pumping large amounts of water into a well to crack the rock under the ground, releasing the oil or gas. As energy prices rise and fossil fuels become scarcer, the practice has been growing in popularity.

The trailer for GasLand states that at least six states have documented some 1,000 incidents of groundwater pollution related to fracking. The documentary interviews people who say they suffered from neurological diseases and other conditions as a result of contaminated water.

The Pennsylvania Office of Homeland Security appears to be at least as heavily focused on anti-oil and gas documentaries as it is on international terrorism. In October, it was revealed that the department had declared the documentary Coal Country to be a "potential catalyst for inspiring 'direct action' protests or even sabotage against facilities, machinery, and/or corporate headquarters."

A Pennsylvania activist Web site reported earlier this month that the department has been monitoring the Twitter feeds of known anti-war activists.